No gas getting to carburetor

[zoulas]

Greetings, 2500 panel, 305E, SM420.

Real strange situation. Went to start it, nothing, would crank, no gas in clear fuel filter. I have had too many fuel pumps go bad due to ethanol gas so I changed the fuel pump.

Still nothing. I checked the fuel line under the truck and I noticed an rubber elbow about 5 feet from the tank. It was original and dry rotted and slow drip of gas.

Ok , I thought I found the problem. Installed a new rubber hose, still nothing.

Put another new fuel pump on with another fuel filter, still nothing .

Checked the gas tank for gas , its completely full.

Removed one end of the fuel hose where it connects to the inlet of the pump. I blew compressed air into the hose and a friend witnessed air and bubbles coming from tank fill spout .

Still nothing, cranks 15 seconds at a time, no fuel enters the completely new clear filter.

I am baffled.

[FetchMeAPepsi]

two things likely. First, have you checked the under-cab fuel filter? It looks like a coke can under the passenger side of the truck. If so, it may need priming.

I just had a conversation with another member about this. When mine went out, I had to prime the fuel pump. It took a while. I hooked up a rubber hose below the pump and stuck a funnel in that. The total had to be above the gas tank's level. Then i poured gas in the funnel and let it clear out the air between the tank and the pump.
Once it was cleared and running back to the tank, plug the hose back in the fuel pump and bob's your uncle. May have had to prime ahead of the pump too once I got it back together, but I can't remember.

Never had to do this with another car or truck, but for some reason it was necessary on mine.

[zoulas]

I checked pretty carefully, I did not see anything the size of a can under the truck. There is a metal line that comes out of the tank, the line goes accross the truck to the passenger side. That's where the rubber elbow was. Then It continues up to the engine area where it becomes rubber again. Then into the pump.

[AZKen]

First thing is to look down throat of carb and operate throttle to see if there is gas squirting in there. No gas? Report to us and See below.
Take off line to pump intake. install a hose at pump intake and put hose into a gas can on the ground (no filter). Take off pump outlet and run it into a container. Take off center tower distributor wire. Crank motor for 15-20 seconds and observe flow into container. Should pulse with good flow. No flow? Report back here. Flows good? reattach output to carb. Put plug wire back on, with pump intake still hosed to a gas can...... start motor. Report.
These tests will lead us to narrow the possibilities. Right now there are too many to start guessing. A testing plan of action is best.

[zoulas]

Ok thank you , will do. Keep in mind, I have a clear fuel filter between the carb and the pump, and its completely dry.

[AZKen]

I realize that. I'm waiting for your detailed explanation of what you discover. Don't mess up the test with a dirty gas can with old gas or use old non-fuel hoses. Don't use filters. Have the gas can near front tire, short hose. don't spill has over motor. If you do, let dry.

[zoulas]

Update, I had a manual siphon so I primed the line. Still nothing, crank for 15 second intervals, finally the gas made it to the filter and it started.

I have changed fuel pumps before and this has never been a problem.

Can the fact that the line was empty from changing the rubber elbow caused this problem?

What are you supposed to do if you run out of gas?

Anyway, thanks for the advice.

[AZKen]

What exactly is a "manual siphon"? A bulb like on a boat tank? or a funnel? Good work, glad you got it started. You just did not crank long enough with choke closed. The fuel pump with suck it pout of the tank, no sweat. All I can say is I have run out of gas. I have also installed a new tank and all fuel lines in my 305 V6 and it started without priming. Just cranking with choke closed and pumping gas pedal. My filters are always before the pump.
I don't dispute other folk's experience.

[zoulas]

Yes a bulb. What difference would having the choke open or closed make, the choke only restricts air flow. It has no impact on gas. No ?

[AZKen]

Even though you "siphoned" it seems it still took a long time. Several 15 second intervals is a long crank. Anyway, about the choke. We are talking about new fuel pumps and possibly no gas in hose or carb. The motor cranks with the starter. The pump is pumping slower than even at idle. So when gas does finally get into the carb/manifold/combustion chamber, you want a good rich load so motor starts as fast as possible to begin pumping faster. So having the choke closed gives you that rich shot. Then you gradually open it, as you know, as motor stabilizes. Having it closed has nothing to do with more pump suction per se. It is just part of a dry start procedure that I thought we were all discussing.

Yes the choke has an impact on gas. Air is part of the gas mixture.

Running out of gas may take the same procedure.

Some say they prime, some say they don't. No argument. What works is good.